Ecology

A community (the sum of all living things in a habitat) of organisms and its environment (biotic and abiotic components), and the interactions between them

• The non-living components of an ecosystem • Affect living things, but are not themselves living • Affect which organisms can live in an area • Important in determining the ecosystem of a region

• A living factor within an ecosystem □ E.g. animal or plant • Include the presence or absence of other organisms that can affect an organism

• Temperature • Light intensity • Texture of soil • pH of soil • Concentration of significant gases in water or air • Nutrient availability • Water availability • Wind speed • Wind direction

• Animals • Plants • Other organisms of their own species • Competitors • Collaborators • Predators • Disease causing organisms • Parasites • Availability of mates

• When individuals compete for a resources that limits their survival (food, habitat) and reproduction • Interspecific competition □ Competition between two organisms of a different species □ E.g. a great white competes with an orca for food • Intraspecific competition □ Competition between two organisms of the same species □ E.g. male birds compete for a mate

□ One organism (predator) kills another organism (prey) and consumes some or all of it for food □ Includes - Animals eating animals (animals preying on other animals) ◊ Lion eating a zebra - Herbivory ◊ Zebra eating grass - Plants preying on animals ◊ Venus fly-trap eating flies

• Interaction between a disease-causing organism and a host can affect the biodiversity of an ecosystem • E.g. Chlamydia (bacteria) can cause disease in koalas, affecting their ability to reproduce

○ A relationship between two or more species that benefits at least one of the species ○ Includes mutualism, parasitism and commensalism

• Both species of a relationship benefit and neither is harmed • E.g. acacia ant and acacia tree

• One species (parasite) benefits at the expense of the other (host) • E.g. fleas on a dog

• One species benefits and the other neither benefits or is harmed • E.g. a bird making a nest on a tree